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1979 /7 Confusion

Posted: Tue Oct 02, 2018 5:34 pm
by daz
The only confusion seems to be with me. Using my vin/engine number my bike comes up as a 1979 /7. However, along with that number on the front steering frame number it says R100. My title says R100. Can anyone shed light on this for me? Most sources I look at say something about an R100T about the same vintage. Can someone show me a picture of an R100T? please. Nothing on my machine says R100/7 OR R100T.
In the long run this information does not mean anything until I need parts. However, I've owned two R100RTs and a fine R80RT and my original R65 and this old bike is just supreme! I expected some old machine that needed a lot of work and money (R50/5) and still be an antique nicknack. This baby is a fine runner. It calls me to ride it. So sweet!

Re: 1979 /7 Confusion

Posted: Tue Oct 02, 2018 6:26 pm
by Rob
Is it running ok? ;)

Re: 1979 /7 Confusion

Posted: Tue Oct 02, 2018 6:31 pm
by Kurt in S.A.
What year was your bike built? You show an '80 model in your sig line but say the bike comes up a '79. If built Sept '78 thru Aug '79 it's a 1979 model; Sept '79 thru Aug '80, it's a 1980 model. In reality I don't think there's a lot of difference in bikes built from '77 thru '80...there are some things but mostly they're the same...clearly things change in 1981. I never really "bought" the /7 moniker given to bikes during this period. I think it's only /7 if it's on the engine badge.

Kurt in S.A.

Re: 1979 /7 Confusion

Posted: Tue Oct 02, 2018 7:14 pm
by daz
Rob it runs superb! It is a fine runner!
Kurt I think it was built after August 1979. But it comes up as a 1979 engine. But man you said just what I wanted to hear when you said, "I think it's only /7 if it's on the engine badge". It just seems to me all these bikes that were 1000 cc were called R100s. Some early ones were called /7 for some reason. AND THAT is what I wonder about. What made the /7 a /7? And was it still called an R100?

All I know for sure is that this R100 runs stronger and is more agile than my previous BMW bikes.

Re: 1979 /7 Confusion

Posted: Tue Oct 02, 2018 7:25 pm
by Kurt in S.A.
daz -

It's my opinion on the /7 thing. BMW was just continuing the trend with the /5, /6, and then the /7. Then after 1978 they must have thought about where that system was going to go...nowhere. So, they dropped it physically from the naming, though it seems to have been used in the background.

I have a book "BMW Profiles - Motorcycles from Berlin 1969-1998". Other than the R100S, RS/RT, and CS they list the following:

R100T - 1978-1980; it shows slightly higher horsepower and (65) compression ratio (9.5:1) than the '78 /7
R100 - 1980-1984; detuned a bit to 8.2:1 but still 67 horsepower; this had the new electronic ignition and probably the "clutch carrier"

You can look at detailed specs here:

http://www.bmbikes.co.uk/bmwmodels.htm

Kurt in S.A.

Re: 1979 /7 Confusion

Posted: Wed Oct 03, 2018 7:02 pm
by daz
Kurt. So from Duane's site he sent me to Phil Hawksley's site. Where you had sent me to another page. According to my engine number, 6170694, my bike was built in December of 1979. Earlier bikes were listed as R100/7. BUT................my bike is listed as R100/7 KW. So what is KW?

R100/7 KW!

Re: 1979 /7 Confusion

Posted: Wed Oct 03, 2018 7:38 pm
by Kurt in S.A.
On this site:
http://www.bmw-z1.com/VIN/VINdecode-e.cgi
It's shown as an R100 /T so it is a 1980 model.

KW is kilowatt which is another way to specify horsepower.

Kurt in S.A.

Re: 1979 /7 Confusion

Posted: Wed Oct 03, 2018 8:13 pm
by daz
Going back to Phil's site it shows the R100/T only built in 1978. Some other source (which?) also states that my vin was built in 1979 as an R100/7. If indeed it was built in December that would make it a 1980 model.

I am aware that KW sometimes refers to kilowatt. I will investigate Phil Hawkleys site further to see if that is what he is saying.

Re: 1979 /7 Confusion

Posted: Wed Oct 03, 2018 8:27 pm
by daz
Well I guess it has 47 KW of power. 63 HP.

Re: 1979 /7 Confusion

Posted: Sat Nov 03, 2018 8:15 pm
by Norm T R100T R1150RT
For what it's worth, I've a 1980 R100T - # 6171152